Case ReportTAD’s for the Derotation of 90° Rotated Maxillary Bicuspids

Hasan Sabah Hasan ,1 Ayshan Kolemen ,2 Mohamed Elkolaly ,3 Anand Marya ,4

Shreyas Gujjar ,5 and Adith Venugopal 4,6

1Orthodontic Department, Khanzad Teaching Center, General Directorate of Hawler-Ministry of Health, Erbil, Iraq2Orthodontic Department, Al-Mustaqbal University College, Babel, Iraq3Orthodontic Department, Royal Dental Center, Alexandria, Egypt4Section of Orthodontics, University of Puthisastra, Phnom Penh, Cambodia5Sri Balaji Dental College, Moinabad, Telangana, India6Department of Orthodontics, Saveetha Dental College, Saveetha Institute of Medical and Technical Sciences, Saveetha University,Chennai, India

Correspondence should be addressed to Adith Venugopal; avenugopal@puthisastra.edu.kh

Received 15 April 2021; Accepted 19 July 2021; Published 29 July 2021

Academic Editor: Andrea Scribante

Copyright © 2021 Hasan Sabah Hasan et al. This is an open access article distributed under the Creative Commons AttributionLicense, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work isproperly cited.

It is undeniable that the advent of extra-alveolar mini-implants for anchorage purposes has revolutionized the field ofOrthodontics. This case report sheds light on an innovative anchorage plan using TADs, to carry out treatment for a15-year-old female patient. The patient reported to the clinic with a chief complaint of rotated second premolars, crowding, anda deep bite. On examination, it was seen that the patient had a Class I skeletal pattern, Class II subdivision molar relationship,90-degree maxillary second premolar rotations, crowding in both the arches, and a deep bite. In this case, the clinicians decidedto use TADs for premolar derotation as it not only provides a pure rotational couple without any deleterious effects on theadjacent teeth but also helps shorten the overall treatment time. The total treatment time for this case was 10 months.

1. Introduction

Any tooth rotation is considered a malocclusion that requiresmanagement by an orthodontist. A rotated premolar leads tonot only occlusal problems but also esthetic concerns [1, 2].Derotation of premolars must be carried out during theinitial phase of fixed orthodontic mechanotherapy [3]. Dero-tation of posterior teeth provides for space that can be uti-lized to relieve crowding in the anterior region. Derotationof the teeth, if carried out with a continuous wire, can leadto unwanted iatrogenic effects on the anchor teeth. There-fore, such rotated teeth need to be derotated using couplemechanics that involve the use of equal and opposite forcesthat bring about pure rotational movement [3, 4].

Patients undergoing fixed orthodontic therapy desiretimely completion of their treatment which is why it is essen-tial for an orthodontist to correct the malocclusion withoutany associated iatrogenic problems. This is where the use of

temporary anchorage devices (TADs) has revolutionizedfixed orthodontic therapy. The judicious use of TADs fortreating orthodontic patients allows an orthodontist to planfor a broader range of movements [5, 6]. This case reporthighlights the use of TADs to treat a 15-year-old patient thatreported to the clinic with a Class I skeletal pattern, a Class IIsubdivision molar relationship, 90-degree maxillary secondpremolar rotations, crowding in the maxillary and mandibu-lar arches, and an anterior deep bite.

2. Case Presentation

A 15-year-old patient reported to the clinic with a chief com-plaint of malaligned teeth and desired orthodontic treatment.Her previous dental history was unremarkable. On extraoralexamination, she had a good facial form and proportion witha straight profile and a minimal display of buccal corridorson smiling. Intraoral examination showed mild crowding in

HindawiCase Reports in DentistryVolume 2021, Article ID 4285330, 8 pageshttps://doi.org/10.1155/2021/4285330

both the maxillary and the mandibular arches, a Class I molarrelation on the right side, and a half-unit Class II relation onthe left side. In addition, the canine relationships were half-unit Class II on both sides, the overjet was normal, therewas a 4mm anterior deep bite, there were missing upperand lower right/left first premolars due to previous extrac-tions, and both the maxillary second premolars were presentwith 90-degree rotations (Figure 1).

The panoramic radiograph showed no abnormalityexcept for missing upper and lower, right/left first premolars.Cephalometric analysis was carried out using WebCeph soft-ware (AssembleCircle Corp., Republic of Korea) and revealeda skeletal Class I relationship, a hypodivergent facial pattern,and proclined upper incisors (Figure 2).

3. Treatment Objectives

(1) Develop a unique anchorage design using TADs forderotation of the maxillary second premolars withoutcompromising the anchorage units

(2) Apply a pure rotational couple force without effect onthe adjacent teeth

(3) Reduce the overall treatment time

(4) Alleviate crowding in both the maxilla and themandible

(5) Correct the anterior deep bite

(6) Correct the molar and canine relationships

4. Treatment Planning

The patient showed a Class I skeletal base, CI II subdivisionmolar relationship, mild crowding, deep bite, hypodivergent

facial pattern, procline upper incisors, and missing upperand lower right/left first premolars and both upper secondpremolars with 90-degree rotation.

The treatment plan was proposed as follows:

(1) Leveling and alignment of the maxillary and mandib-ular arches using fixed orthodontic therapy

(2) Placement of two mini-implants, one in the buccalaspect and the other in the hard palate for derotationof rotated premolars simultaneously while levelingand aligning the arch in order to save time

(3) Closure of residual spaces

(4) After treatment completion, retention with the upperand lowered fixed bonded lingual retainers

5. Treatment Alternatives

Three alternatives were proposed to achieve treatment goals:

(1) The first option was to use a stiff.019 x.025″ SS basearch wire after leveling and alignment in the maxil-lary arch. Reinforcing the anterior anchorage fromthe canine to canine (joining the segment using tightligature ties) as well as a posterior anchorage (byjoining first and second molars together using aligated wire). These anchorage units would be usedto derotate the premolars using power chains fromthe buccal surface of the second premolars to thehook of the molar tube and from the lingual surfaceof the second premolars to the lingual surface of theupper canines (using lingual buttons). Bite turboswould be placed to disocclude the premolars duringthe alignment phase

Figure 1: Pretreatment extra-oral and intra-oral pictures.

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(2) The second option was to again use a stiff.019 x.025″SS wire as the base arch wire. The anterior anchoragewould be the same as the first option, but in this case,the posterior anchorage would be reinforced using aTranspalatal arch bonded to the first maxillarymolars. The derotation would be carried out usingsimilar biomechanics to the first option

(3) The third option was to use TADs as maximumanchorage so that derotation of the premolars couldbe carried out at the same time as the leveling andalignment of the other teeth. Four TADs would beplaced between the upper first molars and secondpremolars buccally, and two would be placedbetween the upper canine and second premolars onthe palatal aspect in the hard palate without usingbite turbos. The TADs would be utilized to derotateusing couple mechanics and maintain an intrusiveeffect on the premolars

After careful consideration of all the three treatmentoptions, the third option was chosen as it shortened the treat-ment time and helped achieve the derotation of the premo-lars without any adverse effects on the adjacent teeth.

6. Treatment Progress

Prior to bracket placement, impressions were taken for fabri-cation of study models, followed by oral prophylaxis. Fixedorthodontic appliance was bonded (slot 0.022-inch, Rothprescription, Discovery, Dentaurum, Germany) with fourlingual buttons (Dentaurum, Germany) on the buccal andlingual aspects of second premolars. At the same time, fourTADs (used as anchorage for derotation of the first premo-lars; 1:6 × 8mm) (Gssem, Korea) were inserted: the firsttwo were inserted in the left/right buccal aspects betweenthe upper second premolars and first molars, and the other

two were inserted in the hard palate between the caninesand second premolars. Both TADs were positioned closeto the occlusal surface to reduce the intrusion effect onpremolars.

Leveling and alignment was started on a 0.014″ NiTiarchwire and followed by a sequence of 0.016″, 0.018″, and0:016 × 22″NiTi along with active power chains (clear contin-uous; Vimel, Koreas, changed every two weeks) from theTADs to the attached buttons on the second premolars. Theelastic chains were placed to derotate the premolars using purecouple forces [7] (Figures 3(a), 3(b), 4(a), and 4(b)).

After completion of the derotation, the buttons wereremoved and brackets were bonded on the second premolars.A.016 x.022″ NiTi wire was placed in the bracket slots of thederotated premolars to align them. Once we were able toengage a.019 x.025″ SS wire in the slot, the palatal TADs wereremoved and the buccal screws were used as anchorage.Closure of remaining spaces was done with hooks placedbetween the canines and the lateral incisors and placementof 6mm closed coil springs from the buccal TAD to the hook.The residual space left after premolar alignment was eventu-ally closed and was helpful in the correction of the anteriordeep bite. Additionally, inter-arch elastics were placedbetween the maxillary and mandibular premolars and firstmolars (1/4-inch, medium, Dentaurum, Germany) to settlethe occlusion. (Figures 3(c), 3(d), 4(c), and 4(d)) Once theocclusion was well settled, the fixed appliance was debondedusing a Carbide bur (TDF-6R, Brassler, USA) and retentionwas provided. Circumferential supracrestal fiberotomy(CSF) was performed on the second premolars to avoid anyfurther chances of relapse (Figure 4(e)).

7. Results

The orthodontic treatment was completed in ten months.Class I molar and canine relationships were obtained on both

Figure 2: Pretreatment cephalogram and panoramic radiograph with analysis of the lateral cephalogram using the Steiner analysis.

3Case Reports in Dentistry

sides with ideal overbite, overjet, correct incisor inclinations,and well-aligned teeth (Figures 5 and 6). The upper andlower midlines were minimally off at the end of treatment(Figure 5). Upper right and left second premolar rotationswere corrected by a customized TAD based approach. Cir-

cumferential supracrestal fiberotomy (CSF) was performedon the derotated premolars to reduce the chances of relapse.The result was retained using a fixed lingual bonded retainerusing a braided stainless steel wire on the upper and lowerarches (Figure 5). Additionally, clear Essex retainers were

(a)

(b)

(c)

(d)

Figure 3: Showing treatment progress; (a, b) simultaneous leveling and alignment stage with derotation of the upper second premolars, (c) enmasse retraction, (d) usage of elastic rings for maximum intercuspation.

(a) (b) (c)

(d) (e)

Figure 4: (a–c) Occlusal pictures showing derotation of premolars using couple mechanics. (d) Space closure. (e) CSF technique.

4 Case Reports in Dentistry

provided to the patient for full time wear. The posttreatmentrecords demonstrate the completed case findings and follow-up after 5 years of treatment (Figure 7).

8. Discussion

Amongst the various treatment alternatives that have beensuggested in this case report, the use of couple mechanicson adjacent teeth is most commonly preferred method.

Unfortunately, due to poor control on the adjacent teeth,such mechanics lead to iatrogenic effects causing furtherdelay in treatment.

Since TADs are being used as anchorage in clinical ortho-dontic treatment widely, there has been a change in treat-ment approach over the last few years [8–14]. Controllinganchorage in certain cases that demand strict anchoragerequirements helps to avoid undesirable tooth movements.However, even a small reactive force can cause undesirable

Figure 5: Posttreatment extra and intraoral images.

Figure 6: Posttreatment cephalogram and panoramic radiograph with analysis of the lateral cephalogram using the Steiner analysis.

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movements and so; it is important to have absolute anchor-age to avoid them [15, 16]. Absolute or infinite anchorageis defined as zero anchorage loss due to the forces appliedto move teeth [17]. It can only be obtained by using dentalimplants as anchors, relying on bone to inhibit movement.Anchorage provided by devices, such as implants or TADsfixed to bone, may be obtained by enhancing the reactiveunit’s support (indirect anchorage) or by fixing the anchorunits (direct anchorage), thus facilitating skeletal anchorage.Orthodontic anchorage is an important factor in obtaininggood treatment results. Stable anchorage is a prerequisitefor orthodontic treatment with fixed appliances and espe-cially for derotation of rotated posterior teeth [18].

A couple is a form of moment. It is created by a pair offorces with equal magnitudes but in opposite directions witha noncoincidental line of action. Because the forces have thesame magnitude but are oppositely directed, this special forcesystem’s net potential to translate the body on which it acts isnil and there is only pure rotation. The magnitude of the cou-ple’s moment (MC) depends on both force magnitude anddistance between the two forces. The moment created by acouple is the sum of the moments created by each of thetwo forces. If there are two forces of a couple system actingon opposite sides of the Cres, their effect to create a momentis additive. If they are on the same side of the Cres, they aresubtractive [19]. Both TADs were placed in proximity tothe occlusal surface reducing the intrusion on second premo-lars during derotation, which also allowed for disocclusion inthe premolar region. The forces originating from bracket-wire interactions are transmitted to tooth structures causingdisplacement (unwanted tipping movement), in this casethe TADs. The TADs not only provide anchorage but alsohelp bring about pure rotational movement and minimizingthe overall treatment time.

Successful orthodontic treatment depends a lot on thevarious strategies that are employed to prevent relapse oforthodontically treated teeth. There are many factors that

may contribute to relapse of a successfully treated malocclu-sion. Growth in an unfavorable manner or tissue reboundmay be some of the factors responsible [20]. Rotated teethare known to relapse more commonly, and the role of theperiodontium has been extensively studied in this regard[20, 21]. Reorientation and lack of reorganization of thesupracrestal fibers are considered the main culprit for suchrelapse [22]. A surgical technique to sever these periodontalfibers was reported by Edwards [23] and was termed cir-cumferential supracrestal fiberotomy (CSF). The theorybehind this was that such a surgery would relieve the ten-sion on the supra-alveolar fibers after derotating a tooth,reducing the chances of relapse [21]. Even with long-term retention using fixed retainers, these sets of fibers havepoor reorientation or reorganizational capacity [24–26].Many further studies have validated the efficacy of CSF as astandard to retain derotations in conjunction to other reten-tive measures [26–28].

Some degree of relapse appeared on upper right centralincisor after five years. However, this corresponded withwhat Al-Jasser et al. [29]; Naraghi et al. [30] found, as theymentioned, that minor relapse in short-term follow-up(1 year) was noted in the maxillary anterior teeth after cor-rection of irregularities compared to a 2 to 4-year period ofbonded retention. This result could be attributed to failuresthat may occur during the retention period without anyfollow-up checkup of the patient. Other contributing factorsto relapse are unfavorable skeletal growth as well as contactpoint discrepancy relative to the dental arch during the reten-tion period. Changes in the arch form, which frequentlyoccur during both the treatment and posttreatment periods,have also shown to influence retention [20].

Clear aligners (CAT) could also have been explored asone of the options for treating this case. However, severalstudies have demonstrated that auxiliaries such as attach-ments and elastics are mandatory in CAT (clear alignerorthodontic therapy) to achieve predictable results. Tooth

Figure 7: Posttreatment extra- and intraoral images 5 years posttreatment.

6 Case Reports in Dentistry

shape has been shown to influence the efficiency of CAT[31–33], during correction of misalignment due to thegeometric interaction between teeth and aligners. Rotationof round-shaped teeth remains one of the less predictablemovements in CAT. According to the existing literature[34, 35], the least accurate movement during CAT is pre-molar rotation. The reduced control of orthodontic toothmovement could be related to the lack of interproximalundercuts between premolars, producing an incorrect forcedistribution. The biomechanical benefits of a TAD-basedanchorage system such as the one used in this study canbe utilized for correcting premolar rotations with alignertherapy too. A further study needs to be conducted, andmore cases need to be published in orthodontic literatureconcerning TADs and aligners in conjunction, to under-stand the possibilities of widening the horizons of ortho-dontic treatment.

TADs may seem like an overkill to derotate severelyrotated teeth, but in fact, they are the most fail-safe mechan-ics that can guarantee no deleterious effects on adjacent teeth,if used with proper training and understanding of orthodon-tic biomechanics.

9. Conclusion

Severely rotated teeth need a specifically designed treatmentplan when using a fixed orthodontic appliance. Using TADsfor correction, such rotated second premolars have a varietyof benefits:

(1) Provide maximum anchorage without any effect onthe adjacent teeth (zero anchorage loss)

(2) Help reduce the overall treatment time, as the derota-tions were being carried out simultaneously along-side leveling and alignment

(3) Use TADs as anchorage allowed for use of purecouple forces without any deleterious side effects

Data Availability

The data that support the findings of this study are availablefrom the corresponding author upon reasonable request.

Consent

The patient’s consent is not required as the patient’s identityis not disclosed or compromised. But following usual proto-col consent was taken and signed by the patient herself andher parents.

Conflicts of Interest

There are no conflicts of interest.

Acknowledgments

The authors wish to thank the patient for her constantsupport throughout the treatment period.

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